This competing continuation application is to support 5 post-doctoral positions for training in lung cellular and molecular biology. The purpose of the program is to provide Ph.D.s and M.D.s (primarily pulmonary physicians) with the specialized expertise required to become independent investigators in lung cellular and molecular biology. The program is based in the Institute for Environmental Medicine while the 11 members of the interdisciplinary faculty are drawn from across the University of Pennsylvania Medical Center. The faculty have a long history of extensive interaction in research and training and routinely share resources and facilities for these purposes. The program is designed for 2-3 years of training for a range of candidates from those who have just received their advanced degree (Ph.D.) or specialty training (M.D.) up to more experienced candidates who desire to reorient their career towards lung-related research. The program provides the trainee with an intensive research experience with one or more preceptors, exposure to a broad range of state of the art technologies with direct relevance to investigation in lung cellular and molecular biology, experience in presentation of data to a critical audience, engendering familiarity and critical analysis of the biomedical literature in lung biology, development of skills in writing a manuscript for publication and a research grant for submission to a funding agency, and training in the ethical conduct of research. Our program has trained 34 post-doctoral fellows including 3 minority scientists during the past 14 years with the majority of graduates continuing a career in biomedical investigation. At the conclusion of the post-doctoral period, trainees will be prepared to obtain an appointment at the junior faculty level in a Medical School or comparable position. RELEVANCE (See instructions): Acute and chronic lung disease represent important threats to human health. The key to understanding the root causes and for designing therapy for most of the diseases is to understand their basic cellular and molecular predispositions and manifestations. This program will train scientists with advanced degrees (MD or PhD) in the rationale and basic methodology for investigating these aspects of lung pathophysiology.